Field of the Invention
This invention relates generally to a biocatalytic reactor and, more specifically, to a biocatalytic reactor to hold a gel-like insoluble biocatalyst.
A catalyst is a substance that accelerates a chemical reaction and enables it to proceed under milder conditions than otherwise possible. Catalysts are in principle not consumed in the reaction they catalyze.
Biocatalysts are catalysts of biological origin such as enzymes or cells containing enzymatic activity. biocatalysts may be either soluble or insoluble.
An enzyme, a soluble protein with catalytic activity, may become insoluble by linking it to an insoluble carrier, through covalent or weaker bonds, by entrapment in a gel or by cross-linking it with a bifunctional reagent such as for instance glutaraldehyde. In the latter cases a gel-like structure insoluble biocatalyst is obtained to which a particulate form can be conferred by mechanical means.
In order to improve its utilization, cells containing enzymatic activity may also be linked to insoluble supports through covalent or weaker bonds and may be entrapped in gel structures such as, for instance, polyacrylamide, calcium alginate and agar.
In the latter cases a gel-like structure insoluble biocatalyst is obtained to which a particulate form can be conferred by mechanical means.
Particulate insoluble gel-like structures as those obtained for enzymes and cells as described above can be used in a variety of reactors. For example they may be used in a batch stired reactor, a continuous stirred reactor (CSTR), a fixed bed reactor and a fluidized bed reactor.
However, due to the poor mechanical properties, high compressibility and lightness of the gel-like insoluble biocatalysts, it has been found that such insoluble biocatalysts are very difficult to utilize in advantageous conditions. In fact the use of such insoluble biocatalysts in packed columns gives rise to unbearable high pressure drops.
Their use in fluidized bed reactors is precluded due to the small difference between their density and that of the substrate solution.
Lastly their poor mechanical properties also precludes or restricts dramatically their use in batch agitated reactors.
Besides the problems in handling the gel-like structure insoluble biocatalysts, in many catalytic reactions, even with other catalysts there is the need to process very viscous particulate substrate solutions.
Another problem which very often occurs is the heavy contamination of packed beds of insoluble biocatalysts due to its proteinaceous nature.
Thus in view of the numerous disadvantages associated with the use of gel-like structure insoluble biocatalysts and/or viscous or particulate substrate solutions, there has been a long felt need for either a method or an apparatus to facilitate the use of such a catalyst or substrate solutions. The present invention serves that need.